Daedalus North Plateau

Descent comes first and it is quick: at the northern point you go down at once, with no pause at the surface. The plan is to drop to around 40 metres off the point, hold out toward the blue and watch open water. Scalloped hammerheads gather where the flow divides, and they are shy of diver noise, so you hover, slow your breathing and let them come. Some mornings they pass on every drop. On others nothing big appears, and sightings are not guaranteed in any season.

Because the current is so strong it is hard to work toward the western side from the tip, so you keep the reef on your right shoulder and drift along the eastern wall. The reef is too big to swim back; a RIB tracks you and collects you after about 45 minutes. Shallower, the wall fills in with dense hard and soft coral, gorgonian fans, clouds of anthias and glassfish and the odd humphead wrasse. Grey reef and silvertip sharks patrol the drop-off, and in season oceanic whitetips come out of the open water, slow and direct. The safety stop is made in open water along the wall or under the boat, and with whitetips around it becomes the part of the dive that needs managing.

The reef's east and west walls converge at the northern point, and the prevailing north-to-south current splits against it west of the tip, often drawing hammerheads to the reef at about 40 metres. The northern tip and its east wall are exposed to upwelling and offer the highest probability of pelagic encounters on the reef, with oceanic whitetips and grey reefs working the wall. Hammerhead encounters here are usually brief and deep, often over in seconds. Guides run the tip early, on the morning's incoming current, when schooling has most often been documented.

The steamer Zealot is usually dated to 1876, when she struck the Daedalus shoals, and she is the reef's one documented wreck. The hull lies down the steep slope of the north wall, the bow at about 75 metres and the stern at about 110, which puts it with technical divers. Steel beams from her cargo are scattered on the reef wall near the tip, well above the hull, and they are the nearest thing to a wreck a recreational diver reaches here.

Liveaboards typically overnight at the reef and run up to three dives a day, so the deep opening phase at the tip repeats. A 5 mm wetsuit suits the whole 22 to 30 C range, and the long open-water stops are where you feel the chill.

Boats mostly reach the reef from mid-March to mid-December. A winter trip planned for whitetips may lose the reef to weather, so keep a day or two of slack at either end of the itinerary. A surface marker buoy and a computer are essential for the open-water stop and the pickup.